When controlling the operation of moving bodies, travel of the moving body is controlled so that a rear end collision or bumping between moving bodies, or a collision between an obstacle and the moving body does not occur.
If the moving body itself is to be liable for a rear end collision or bumping, then the information necessary to avoid this is; the distance in front of the moving body to another moving body (distance between moving bodies), or the distance in front of the moving body to an obstacle (for example in the case where the moving body travels along a rail, this also includes the distance to the end of the rail or to a damaged portion of the rail), the travelling speed of the moving body, and other information.
For example, taking a train as an example for describing the moving body, then with conventional train travel control systems, there is the fixed block system where the railroad track is divided into a plurality of block sections, and the presence or absence of a train is detected for each of the block sections, and the speed of the rear train is controlled corresponding to the inter-train distance (number of block sections) between a front train and the rear train, to thereby avoid a rear end collision.
The conventional fixed block system however is a centralized system which convergently detects the location of each train from the ground side. There is therefore the likelihood that for example a fault in one of the block sections will become an obstacle for the entire railroad track of the lines which include this block section. Moreover, there is the problem in that it is not easy to modify the design for the block section, and there are problems with flexibility of the operating control and with system maintainability and the like.
Moreover, with the conventional fixed block system, the train presence detection uses the fact that two rails of the block section are electrically short circuited by the train wheels. Therefore if for example the rail surface is rusty so that resistance is increased, then even though a train may be present, the short circuit between rails due to the train wheels becomes incomplete so that there is the possibility for example that the detection shows the train to be absent. Essentially therefore the contact resistance between the rails and the wheels becomes a problem from a safety management point of view. Moreover, since an electrical signal is transmitted to the rails on which the train travels for each block section, it is necessary to insulate the rails of adjacent block section pairs so that an electrical signal does not flow in from the adjacent block sections.
Furthermore, as another method of controlling travel of a moving body, there is the GPS (Global Positioning System) where the moving body detects its own position using a communication satellite. However with the GPS, in order to know the distance to another moving body (distance between moving bodies), a communication system between the moving bodies or between the moving body and the ground must be provided separately. Moreover, with a communication satellite, maintenance of the satellite is not possible.
A device for a moving body to detect its own position and speed using ultrasonic wave signals, has been proposed by one of the present inventors (Unexamined Japanese Patent Publication No. 4-362463). However with this device, travel of respective moving bodies is controlled by having a relationship between adjacent moving bodies. Moreover, there is no generation of information necessary for travel control.
The present invention takes into consideration the abovementioned situations, with the object of providing a moving body control apparatus with good operating control flexibility and system maintainability, by having a decentralized control system wherein by transfer of ultrasonic wave signals between moving bodies, information for moving body travel control is generated only between moving bodies without intervention from the ground side.